1. Field of the Invention
The present invention relates to a stabilizer link rod for linking to a suspension arm a stabilizer rotatably installed to the chassis of an automobile, and a method of manufacturing the stabilizer link rod.
2. Description of the Prior Art
In automobiles, a stabilizer uses a torsion bar spring between the suspension arm and chassis in such a manner as to create a moment against a rolling of the automobile chassis and not to act as spring against a vertical oscillation of the chassis to reduce the rolling of the chassis, for thereby improving the running stability. Generally, the stabilizer is a U-shaped bar of which the central portion is made of a torsion bar spring. Opposite ends of the stabilizer are used as arms. Each of the end arms is installed to the suspension arm by means of a ball joint, and the central portion of the stabilizer is installed rotatably to the car chassis by means of a rubber cushion or bush.
A ball joint used for installing each end arm of the stabilizer to the suspension arm namely, stabilizer link rod, has a structure shown by way of example in FIG. 1. In this prior-art stabilizer, a steel connecting rod 100 has a steel socket 101 fixed (welded) to either end thereof as shown. The socket 101 is open at both the top and bottom thereof and has an annular abutment 101a at the top thereof. The socket 101 has fitted therein a synthetic resin-molded ball seat or bearing 103. A ball stud 102 is fitted at a spherical head 102a thereof in the synthetic resin-molded ball seat or bearing 103. The bearing 103 is open at the top thereof and has a bottom 103b. The bearing 103 abuts at a top end face 103a thereof upon the annular abutment 101a of the socket 101. The socket 101 is closed at the bottom thereof with a plate 104 fixed to the bottom end by caulking. Thus the bearing 103 is pressed by the closing plate 104. One of the ball studs 102 of the ball joint is linked to the end arm of the stabilizer while the other ball stud 102 is linked to the suspension arm, so that input from the wheel is transmitted to the stabilizer.
The steel socket 101 welded to each end of the prior-art steel rod 100 is usually formed by cold forging. Since the rod and socket are made of steel, the stabilizer cannot have a reduced weight. Further, the socket has to be joined to the rod by welding. Therefore, the manufacturing costs for the prior-art stabilizer cannot be reduced.
The bearing 103 of the prior-art stabilizer is molded as a whole in a synthetic resin. To grasp the head 102a of the ball stud 102 in the bearing 103. the bearing 103 is deformed with the closing plate 104 which is fixed later, or the socket 101 is deformed by caulking. Therefore, it is difficult to grasp the head 102a in the bearing 103. The bearing 103 may possibly be damaged or degraded in property as the case may be.
Furthermore, it is difficult to reduce the weight of the prior-art stabilizer since the rod 100 and socket 101 are made of steel. Also, an additional work is necessary to close the bottom opening of the socket 101 with the plate 104.
Moreover, a dust cover 105 is finally installed to the socket 101. One end of the dust cover 105 is secured to the outer top perimeter of the socket 101 using a C-shaped clip, caulking ring or the like. Therefore, installing the dust cover 105 leads to an increase of manufacturing steps and parts and thus to an increase of manufacturing cost. Since the socket 101 is made of steel, it increases the weight of the stabilizer. A lighter stabilizer has been desired.